The ability to mix various materials with fluids on a continuous high volume basis has been a goal in various industries for many years. The oil and gas drilling industry, for example, mixes large quantities of drilling fluid for downhole circulation during drilling. Such fluids are both water and oil based, and the materials added are varied, such as bentonite, barite, polymers, and many other liquids and powders. Other applications include a number of industries involving polymer mixing, water treatment, slurry walls, clay slurries, lime slurries, solubilizing dry chemicals, and horizontal drilling for industrial applications, such as river crossings.
Devices commonly utilized for such purposes, particularly in the oil and gas drilling industry, an eductor assembly generally, and a particular adaptation of an eductor assembly known as a venturi hopper, of the type having a base fluid inlet, a material funnel for feeding materials, a substantially vertical hopper throat, a hopper throat valve, and an eductor, having a mixing chamber, a jet, and a venturi discharge/diffuser which receives and discharges the jetted fluid, along with the materials drawn from the hopper throat into the jetted fluid by the venturi effect. Also utilized are low velocity shearing devices, which create turbulence in the fluid by moving the fluid through low shear plates and/or static mixers, as well as, high velocity shearing devices which typically involve dividing the fluid into two flows, then rejoining the flows in opposition to each other, the interaction causing beneficial impact and turbulence. The high velocity shearing devices typically involve jetting the fluid for additional turbulence.
The above devices have been combined into various systems, but such systems suffer from a lack of routing options among the devices, ineffective methods for adding special chemical powders, such as powdered polymers, ineffective secondary materials feed inlets in addition to the primary material funnel feed, a lack of routing for effective backflowing of the shearing devices, a failure to combine both the low and high velocity shearing devices, cumbersome service access to the jet, ineffective use of available space on location, and/or redundant power sources.
An example is U.S. Pat. No. 5,765,946 which provides a continuous static mixing apparatus and process which includes an eductor assembly, at least one "mixing disk," which create turbulence, and routing for the interaction of opposing flows. The processes which both the eductor and the mixing disks, include the base fluid entering either the eductor or the mixing disks first, then the other in series. No other routings are shown for the combined devices. The drawings do not depict alternate routings for an individual embodiment, nor is a routing suggested for backflowing through the mixing disks. More than one materials entry point into the eductor assembly is generally suggested, although the eductor assembly actually shown includes what appears to be a hopper throat only.
U.S. Pat. No. 5,322,222 discloses a spiral jet mixer for mixing fluids, which has a first inlet nozzle for the introduction of a primary fluid, a mixing chamber having a diverging wall and a converging wall, a plurality of angled helical passageways in the diverging wall for introduction of a secondary fluid into the mixing chamber in a spiraling turbulent, initially convergent flow pattern. The device is marketed by VORTEX VENTURES, INC., and is referred to as a radial eductor.
Another example is the LOBESTAR.TM. Mixing Eductor by VORTEX VENTURES, INC., includes a typical venturi hopper, modified to provide a "radial premixer," which has an inner liner within the throat, through which a substantial portion of the base fluid is routed, the base fluid being tangentially directed through the liner to create a vortex, the materials from the hopper being premixed, to some extent, with this portion of the base fluid, as the material is drawn into the eye of such vortex. The base fluid entry into the hopper throat is substantially lower than the hopper throat valve. Also included is a small "vacuum gauge and chemical injection inlet" which discharges into the mixing chamber. This device diverts an unacceptably large amount of the base fluid from the jet, requiring a lower amount of jetted fluid to draw a larger amount of"pre-mixed" base fluid and materials into the venturi discharge. The device also allows a vacuum to be created against a closed hopper valve, in cases where the "chemical injection inlet" is the sole source of materials. Such a vacuum is undesirable in that accumulations of materials can be created when partially wetted materials are drawn into the hopper throat area beneath the hopper throat valve. Similarly, the "chemical injection inlet" is too small to use for the introduction of powdered chemicals, and is impractical for use in applications in which this inlet is the sole source of materials being added to the base fluid. This impracticality is made worse by the reduction in vacuum caused by the routing of a substantial amount of fluid through the radial premixer. An additional problem is the ineffective access to the jet for replacement.
Another example is the SHEAR TEARER.TM. In-Line Shearing device, which provides a low velocity shearing device to be combined with a venturi hopper, in parallel only, with no high velocity shearing device, and no routing option for using the devices in series, no routing option system bypass, and no routing option for backflowing the fluid through the shearing device.
An additional example is the JET SHEART.TM. II, continuous mixing system by Flo Trend.TM. Systems, Inc., which includes a venturi hopper in series with two shearing devices, with a routing option to bypass the shearing devices, but not the venturi hopper. No routing option is provided for backflowing through the shearing device, and no low speed-shearing device is provided.
Similar to this device is the JET SHEAR.TM. manufactured by Flow Process Technologies [S] Pte. Ltd., in which the primary difference is the orientation of the fluid recombination path in the shearing device, changing from an angled recombination to an inline recombination of the fluid. The entering liquid is divided into two equal and opposing streams through a yoke assembly. These streams are directed into a mixing chamber through discs containing nozzles located in each end of the mixing chamber, which form the lateral boundaries of the mixing chamber. These nozzle plates are positioned to oppose each other. The nozzles contained in these respective plates are equally spaced on a circle located near the outer perimeter of the nozzle plates and are precisely angled with respect to the horizontal and vertical planes of the mixing chamber. The nozzles are identical in both plates, and since these plates are geometrically opposed, the liquid streams directed through each nozzle plate are moving in opposite rotational directions, one clockwise and one counterclockwise. Product literature suggests installing the device in parallel with the drilling rig mixing hopper.
U.S. Pat. No. 4,664,528 discloses an apparatus and method for mixing water in a water-soluble emulsion polymer, which includes a pump means, a static mixing means, and a mixing chamber means, where a first circulation means connects the pump means to the mixing chamber means, a second circulation means connects the pump means to the static mixing means, and further connects the static mixing means to the mixing chamber means. A third circulation means connects the static mixing means to the mixing chamber means. Flow control means selectively circulates the combined stream of the water and the polymer alternatively through the first circulation means, the second circulation means, or the third circulation means. The pump means has an inlet adapted to receive and combine the water and the emulsion polymer to form a combined stream of water and emulsion polymer. The apparatus has a static mixing means for mixing water and polymer, having an inlet adapted to receive and combine the water and the emulsion polymer to form the combined stream. The mixing chamber means produces a homoceneous mixture of the water and emulsion polymer.
A typical venturi hopper is the Phoenix Solids Control Systems device by Harrisburg/Woolley. In at least one device, Harrisburg/Woolley has utilized the mixing chamber suction by running a line from the mixing chamber to the top of the material funnel for the purpose of vacuuming "dust" generated during the addition of bulk materials, such as bentonite.
The SECO SUPER SHEAR.TM. by ITS Drilling Services is a variable speed-shearing device, which is installed either downstream or upstream of the rig-mixing hopper. It utilizes a SECO HOMOGENIZER, which is a field version of a colloid mill, and requires an electric motor. ITS Drilling Services also provides the POLYGATOR.TM. SHEARING SYSTEM, which also uses a SECO HOMOGENIZER.
The Geolograph-Pioneer SIDEWINDER.TM. uses two-stage cyclonic action which hydrates, mixes and blends mud additive particles to uniformity before discharge into the mud system. In this device the liquid is routed behind a liner in such a manner as to create a vortex into which dry bulk materials are fed prior to discharge of the liquid from the device.
U.S. Pat. No. 5,486,049 discloses a fluid and material mixing device involving a plurality of passages, with some embodiments including mixing means such as static mixers.
U.S. Pat. No. 1,730,453 discloses internal baffles along the length of an inlet manifold for an internal combustion engine.
U.S. Pat. No. 1,885,559 discloses a fuel mixing device for internal combustion engines, including a device having a plurality of mixing units within individual conduits from the carburetor to each cylinder.
U.S. Pat. No. 2,922,441 discloses a bypass or diversion fitting adapted to be inserted in the main line of a forced-feed circulatory heating system.
U.S. Pat. No. 3,870,283 discloses a method and apparatus for mixing a powder, such as lime, in flowable substance such as sewage sludge in which the flowable substance is introduced into a mixing chamber having an outlet, at a level below the outlet, in such a way that the flowable substance is induced to flow out of the outlet in a vortex flow, with the powder being introduced into the vortex flow.
U.S. Pat. No. 4,068,830 discloses a mixing method and system for the thorough intermixing of liquids of widely different viscosities using at least one perforated plate in the line of flow ahead of a conventional static mixer.
U.S. Pat. No. 4,518,568 discloses a system for preparing water-based drilling fluid having an enclosed mixing chamber with inlets for conveying supplies of water, heated fluid, and drilling fluid components into the interior of the mixing chamber, barrel means for retaining a supply of salt, piping means for conveying fluid from the interior of the mixing chamber to the interior of the barrel means and for conveying fluid from the interior of the barrel means to a suction pit, and additional piping means for conveying fluid from the suction pit to the interior of the mixing chamber and for conveying fluid from the interior of the mixing chamber directly to the suction pit.
U.S. Pat. No. 4,753,535 discloses a device for the mixing of two fluids in a conduit, the device being within the conduit substantially along the longitudinal axis of the conduit. A feed port introduces the second fluid into the device, which has miscellaneous mixing elements.
U.S. Pat. No. 5,560,710 discloses a process for continuously mixing streams of at least two fluid media, used particularly in reburning or progressive combustion and for secondary NO.sub.2 reduction in flue gases from industrial furnace plants, where an auxiliary gas stream is injected into a main gas stream by means of swirl-momentum nozzles, which impart a characteristic axial impulse and an angular impulse to the fluid.
The above patents are incorporated herein by reference, for all purposes, as if set forth herein at length.
What is needed is a compact, unified system providing options for routing the fluid through the venturi hopper assembly and the shearing device in series, routing the fluid through each such device individually, routing the fluid to bypass any one or all of such devices, and routing the fluid in two directions through the shearing device, and which further provides a choice of high or low velocity shearing devices, including a combination high and low velocity shearing device, and which further provides a practical and effective process to introduce materials, bulk or otherwise, to the venturi hopper mixing chamber through an inlet other than, and to the exclusion of, the material funnels.
The apparatus and methods of our invention are manifested in numerous embodiments, which address, in whole or in part, the current need for a compact, unified system providing options for routing the fluid through the venturi hopper assembly and the shearing device in series, routing the fluid through each such device individually, routing the fluid to bypass any one or all of such devices, and routing the fluid in two directions through the shearing device, and which further provides a choice of high or low velocity shearing devices, including a combination high and low velocity shearing device, and which further provides a practical and effective process to introduce materials, bulk or otherwise, to the venturi hopper mixing chamber through an inlet other than, and to the exclusion of, the material funnels.